A spokesman said: "Police would like to speak to the person pictured in the CCTV stills as they may have important information that could assist the investigation."

Anyone who recognises him or who has any information that could help to locate the trailers is asked to email David.Laverick@northyorkshire.pnn.police.uk or call 101, select option 2 and ask for David Laverick.

The second trailer taken from the depot in Castleton.

Information can also be passed on anonymously to Crimestoppers on 0800 555 111.